A molten salt storage tank with side pipes

Abstract

This invention relates to the field of molten salt energy storage technology, and particularly to a molten salt storage tank with side pipes. By incorporating pipes on the side of the tank, the hot molten salt, upon injection, creates an effective vortex at the bottom of the tank, accelerating the heating process of the cold molten salt inside and achieving a more uniform temperature distribution. Furthermore, by utilizing the kinetic energy generated during the injection of hot molten salt, the vortex formation promotes rapid heat transfer and dispersion, significantly reducing the maximum boundary temperature difference within the tank. Therefore, this technical solution not only improves thermal storage efficiency but also reduces thermal stress caused by temperature differences, helping to extend the tank's service life and reducing the risk of molten salt freezing. In other words, it not only solves the temperature difference and thermal stress problems inherent in traditional molten salt storage tanks but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt.

Description

Technical Field

[0001] This invention relates to the field of molten salt energy storage technology, and more particularly to a molten salt storage tank with side pipes. Background Technology

[0002] Molten salt energy storage technology is an advanced thermal energy storage method widely used in solar power generation and other industrial thermal processes. Molten salt tanks utilize molten salt as the energy storage medium, exhibiting superior performance in collecting, storing, and transferring high-temperature thermal energy due to its high melting point and excellent thermal stability. In solar thermal power plants, this energy storage method allows for continued power generation even when sunlight is insufficient, greatly improving the flexibility and economy of energy utilization.

[0003] However, existing molten salt storage tank technology faces several technical challenges. One of these is the density variation of the molten salt inside the tank at different temperatures, leading to severe stratification and the formation of a thermocline. This thermocline affects the heat exchange efficiency of the molten salt, limiting the uniform extraction and storage of heat energy. Furthermore, extreme temperature differences within the tank cause uneven thermal stress on the tank body, which may affect the structural integrity and service life of the tank.

[0004] Therefore, there is an urgent need for a molten salt storage tank with side pipes to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a molten salt storage tank with side pipes, which not only solves the problems of temperature difference and thermal stress in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt.

[0006] This invention provides a molten salt storage tank with side pipes, comprising:

[0007] The tank body has a first molten salt inlet at the top and a first molten salt outlet at the bottom. A first molten salt cavity is formed inside the tank body to allow molten salt to flow. The first molten salt inlet, the first molten salt cavity, and the first molten salt outlet are connected.

[0008] A pipe is provided on the side of the tank body. A second molten salt inlet is provided at the top of the pipe and a second molten salt outlet is provided at the bottom. A second molten salt cavity is formed inside the pipe for the flow of molten salt. The first molten salt cavity and the second molten salt cavity are connected through the second molten salt inlet and the second molten salt outlet. The first molten salt inlet is located above the second molten salt inlet, and the first molten salt outlet is located below the second molten salt outlet.

[0009] When the molten salt storage tank is in operation, hot molten salt can enter the first molten salt cavity from the first molten salt inlet, and can enter the second molten salt cavity from the first molten salt cavity through the second molten salt inlet, and finally flow out from the second molten salt outlet to mix with the cold molten salt located at the bottom of the tank.

[0010] As can be seen from the above solution, the molten salt storage tank with side pipes provided by this invention, by setting pipes on the side of the tank body, can form an effective vortex at the bottom of the tank body when hot molten salt is injected into the tank, thus accelerating the heating process of the cold molten salt inside the tank and achieving a more uniform temperature distribution; moreover, by utilizing the kinetic energy generated when hot molten salt is injected, the formation of vortices promotes the rapid transfer and dispersion of heat, significantly reducing the maximum boundary temperature difference inside the tank. Therefore, the above technical solution not only improves the heat storage efficiency, but also reduces the thermal stress caused by temperature difference, which helps to extend the service life of the storage tank and reduces the risk of molten salt freezing. That is, it not only solves the problems of temperature difference and thermal stress existing in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A schematic diagram of a molten salt storage tank with side pipes provided in one embodiment of the present invention;

[0013] Figure 2 A temperature field simulation diagram of a molten salt storage tank with side pipes provided for one embodiment of the present invention;

[0014] Figure 3 A velocity field simulation diagram of a molten salt storage tank with side pipes provided for one embodiment of the present invention.

[0015] Figure label:

[0016] 1-Tank body;

[0017] 11-First molten salt import;

[0018] 12 - First molten salt outlet;

[0019] 13-First molten salt chamber;

[0020] 2-Pipeline;

[0021] 21-Second molten salt import;

[0022] 22-Second molten salt outlet;

[0023] 23-Second molten salt chamber;

[0024] 3-Molten salt pump. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see Figure 1 One embodiment of the present invention provides a molten salt storage tank with side pipes, the molten salt storage tank comprising a tank body 1 and pipes 2, wherein:

[0027] The tank body 1 has a first molten salt inlet 11 at the top and a first molten salt outlet 12 at the bottom. A second molten salt cavity 23 is formed inside the tank body 1 to allow molten salt to flow. The first molten salt inlet 11, the second molten salt cavity 23 and the first molten salt outlet 12 are connected.

[0028] Pipeline 2 is located on the side of tank 1. A second molten salt inlet 21 is provided at the top of pipeline 2 and a second molten salt outlet 22 is provided at the bottom. A second molten salt cavity for molten salt to flow is formed inside pipeline 2. The second molten salt cavity 23 and the second molten salt cavity are connected through the second molten salt inlet 21 and the second molten salt outlet 22. The first molten salt inlet 11 is located above the second molten salt inlet 21 and the first molten salt outlet 12 is located below the second molten salt outlet 22.

[0029] When the molten salt storage tank is in operation, hot molten salt can enter the second molten salt chamber 23 from the first molten salt inlet 11, and can also enter the second molten salt chamber 23 from the second molten salt inlet 21, and finally flow out from the second molten salt outlet 22 to mix with the cold molten salt located at the bottom of the tank 1 (which can be used for mixing). Figure 2 (Red indicates hot molten salt, and blue indicates cold molten salt).

[0030] In this embodiment, by providing a pipe 2 on the side of the tank 1, the molten salt can form an effective vortex at the bottom of the tank 1 when it is injected into the storage tank (which can participate in...). Figure 3(The white part represents vortices), which accelerates the heating process of the cold molten salt inside the tank, achieving a more uniform temperature distribution. Furthermore, by utilizing the kinetic energy generated during the injection of hot molten salt, the formation of vortices promotes rapid heat transfer and dispersion, significantly reducing the maximum boundary temperature difference within the tank. Therefore, this technical solution not only improves thermal storage efficiency but also reduces thermal stress caused by temperature differences, helping to extend the service life of the storage tank and reducing the risk of molten salt freezing. In other words, it not only solves the temperature difference and thermal stress problems inherent in traditional molten salt storage tanks but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt.

[0031] It is understood that the molten salt storage tank provided in this embodiment of the invention is a single-tank structure. By designing a traditional single-tank tank (i.e., setting a pipe 2 on the side of the tank body 1), the thermal management and structural performance of the molten salt thermal storage single tank can be optimized. Specifically, the advantages of this design are:

[0032] 1) Reduce the impact of temperature difference and stress: By introducing a mixed circulation of hot and cold molten salts into the side pipe, the temperature difference between hot and cold molten salts inside the tank can be significantly reduced, thereby alleviating the thermal stress caused by the temperature difference, protecting the tank structure, and extending its service life.

[0033] 2) Disruption of the thermocline: The addition of side pipes increases the dynamics of molten salt flow, and the resulting eddy current effect can effectively disrupt the thermocline within the tank, promoting a more uniform distribution of the molten salt. This change in flow pattern improves heat exchange efficiency, making heat energy storage and extraction more efficient and balanced.

[0034] In summary, the side pipe design of this invention not only solves the temperature difference and stress problems existing in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt, bringing new possibilities for the application and development of molten salt energy storage technology.

[0035] In one embodiment of the present invention, the structure of the pipe 2 is arc-shaped, which can ensure that the resistance of the molten salt flowing through the second molten salt cavity 23 is minimized, thereby reducing the kinetic energy loss of the molten salt.

[0036] In one embodiment of the present invention, the number of second molten salt inlets 21 is at least two, that is, hot molten salt can flow out of the first molten salt cavity 13 through at least two pipes 2, thereby increasing the flow rate of hot molten salt entering the pipes 2.

[0037] In one embodiment of the present invention, the number of second molten salt outlets 22 is at least two, that is, hot molten salt can flow into the first molten salt cavity 13 through at least two pipes 2, which can increase the flow rate of hot molten salt mixed with cold molten salt, thereby achieving a better uniform temperature distribution and reducing the maximum boundary temperature difference in the tank.

[0038] It should be noted that in molten salt energy storage systems, the thermocline describes the temperature stratification phenomenon caused by thermal convection and conduction within the molten salt tank. This involves the formation of a rapidly changing temperature zone within the tank, which significantly impacts the efficient storage and extraction of thermal energy. The formation of a thermocline in a molten salt tank can affect the efficiency of thermal energy storage and extraction because the temperature gradient leads to uneven distribution of thermal energy within the tank.

[0039] The second molten salt outlet 22 is located at the lower part of the tank 1. If it is too high, some cold molten salt at the bottom will not be effectively heated; if it is too low, it will not be able to form a good vortex disturbance in the tank 1. If the molten salt velocity at the second molten salt outlet 22 is too slow, it will not be able to efficiently solve the effects of the thermocline and temperature difference; if the velocity is too fast, it will result in a large pressure difference between the inside and outside of the tank 1, which may easily lead to damage to the tank. Therefore, it is necessary to optimize the design of the location and molten salt flow rate of the second molten salt outlet 22.

[0040] In one embodiment of the present invention, the height difference between the second molten salt outlet 22 and the first molten salt outlet 12 is not less than one-tenth of the height of the tank 1 and not greater than one-eighth of the height of the tank 1.

[0041] In one embodiment of the present invention, the pipeline 2 is equipped with a molten salt pump 3.

[0042] In this embodiment, by optimizing the setting position and molten salt flow rate of the second molten salt outlet 22, that is, by constraining the height difference between the second molten salt outlet 22 and the first molten salt outlet 12 and by setting the molten salt pump 3 in the pipeline 2, it is possible to further ensure that a uniform temperature distribution can be achieved and reduce the maximum boundary temperature difference in the tank.

[0043] In one embodiment of the present invention, the flow rate of molten salt flowing out from the second molten salt outlet 22 is related to the radius of the tank 1, the type of molten salt, and the height difference.

[0044] It should be noted that the larger the tank radius, the greater the molten salt flow rate; the two are directly proportional. The type of molten salt determines its flow properties; the better the flow properties, the greater the molten salt flow rate; the two are also directly proportional. The greater the height difference, the greater the molten salt flow rate; the two are also directly proportional. Ultimately, the molten salt flow rate depends on the molten salt pump 3, and the above three factors are the key parameters constraining the molten salt flow rate. In other words, the final molten salt flow rate needs to ensure a good eddy current effect; it cannot be too fast or too slow.

[0045] The following describes the usage process of the molten salt storage tanks mentioned above:

[0046] During use, hot molten salt enters the first molten salt chamber 13 from the first molten salt inlet 11 at a certain speed. At the same time, some hot molten salt flows in from the side pipe 2. The molten salt pump 3 applies a speed to the molten salt in the pipe 2, so that the speed of the molten salt in the second molten salt chamber 23 is greater than that in the first molten salt chamber 13. Finally, the hot molten salt in the pipe 2 flows out from the second molten salt outlet 11, forming a vortex below the tank 1. This causes the temperature of the cold molten salt to rise rapidly, reducing the extreme temperature difference between the cold and hot molten salts in the tank 1. This can reduce the stress on the tank 1, and the vortex can effectively destroy the thermocline layer inside the tank 1.

[0047] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0048] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A molten salt storage tank with side pipes, characterized in that, The molten salt storage tank is a single-tank structure, comprising: The tank body has a first molten salt inlet at the top and a first molten salt outlet at the bottom. A first molten salt cavity is formed inside the tank body to allow molten salt to flow. The first molten salt inlet, the first molten salt cavity, and the first molten salt outlet are connected. A pipe is provided on the side of the tank body. A second molten salt inlet is provided at the top of the pipe and a second molten salt outlet is provided at the bottom. A second molten salt cavity is formed inside the pipe for the flow of molten salt. The first molten salt cavity and the second molten salt cavity are connected through the second molten salt inlet and the second molten salt outlet. The first molten salt inlet is located above the second molten salt inlet, and the first molten salt outlet is located below the second molten salt outlet. When the molten salt storage tank is in operation, hot molten salt can enter the first molten salt cavity from the first molten salt inlet, and can enter the second molten salt cavity from the first molten salt cavity through the second molten salt inlet, and finally flow out from the second molten salt outlet to mix with the cold molten salt located at the bottom of the tank, so that the temperature of the cold molten salt rises rapidly, reducing the extreme temperature difference between the hot and cold molten salts in the tank, and forming a vortex at the bottom of the tank to destroy the thermocline layer in the tank. The height difference between the second molten salt outlet and the first molten salt outlet is not less than one-tenth and not greater than one-eighth of the tank height. The pipeline is equipped with a molten salt pump to reduce the maximum boundary temperature difference inside the tank. The flow rate of molten salt exiting the second molten salt outlet is correlated with the radius of the tank, the type of molten salt, and the height difference to ensure the generation of eddy current effect.

2. The molten salt storage tank according to claim 1, characterized in that, The pipe has an arc-shaped structure.

3. The molten salt storage tank according to claim 1, characterized in that, The number of second molten salt inlets is at least two.

4. The molten salt storage tank according to claim 1, characterized in that, The number of the second molten salt outlets is at least two.

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